Standard sized blinds are anywhere from 24 x 72 - 72 x 72 off the shelf at your local hardware stores.
How do you make a wide Roman shade?
https://www.youtube.com/watch?v=VAMEH35XQzc
Do Roman blinds work on wide windows?
The added width of wide roman blinds makes them ideal for huge expanses of glazing. ... Since they are made of longer horizontal fabrics, they can easily fit even the widest windows.Mar 11, 2021